John Williamson, the founder of the sexually liberal Sandstone Retreat, has died at the age of 80.

According to an Associated Press report on his death, Williamson died of cancer on March 24 in Reno, Nevada.

Williamson and his wife, Barbara, were famous for founding the Sandstone Foundation For Community Systems Research near Los Angeles in 1969. The resort, which Williamson claimed was geared toward reducing population growth, was infamous for its open embrace of nudity and sexual liberty. Before founding the retreat, Williamson was an engineer and project manager at Lockheed Aircraft. He had also owned his own electronics company, which he sold to buy the land for the Sandstone Retreat. From the Sandstone website:

It was February, 1966 when we, (John and Barbara), met in an intense business environment. Five weeks later we decided to marry and compared notes we had made about the world we would have to live in thereafter. We decided there were many things wrong or questionable with that world under close examination. Many others we met in our travels felt the same. So many, in fact, we were convinced to abandon our comfortable, high paid corporate lifestyles and leap off the cliff into unknown waters.

The Sandstone Retreat was the subject of a 1975 documentary titled Sandstone. The retreat became more infamous in the late 70s as celebrities began visiting the site.

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(Image courtesy the Sandstone Retreat)